Topic
Excimer
About: Excimer is a research topic. Over the lifetime, 3725 publications have been published within this topic receiving 75104 citations.
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TL;DR: In this article, a new class of C∧C* platinum(II) complexes with excimer formation enhances the quantum yield while shortening the phosphorescence lifetime was reported.
57 citations
TL;DR: Aqueous solution of micelles prepared from novel PS-b-PNIPAM with fluorescent group CEA at the junction between two blocks displays logical responsive switches on temperature and fluorescence.
57 citations
TL;DR: In this article, the authors used fluorescence depolarization to characterize energy migration in glassy solutions of copolymers with methyl methacrylate and found that the concentration of excimer sites in the macromolecule will be proportional to the fraction of links between aromatic species.
Abstract: Energy migration and intramolecular excimer formation have been studied in a series of copolymers comprising 1-vinylnaphthalene, 2-vinylnaphthalene, and styrene with methyl methacrylate. The technique of fluorescence depolarization was used to characterize energy migration in glassy solutions of the copolymers. The extent of energy migration in these copolymers is determined by the mean sequence length of aromatic species la. Assuming that excimer formation occurs as a result of nearest-neighbor interactions, the concentration of excimer sites in the macromolecule will be proportional to the fraction of links between aromatic species faa. It is proposed that these sites are populated via energy migration from the site of absorption. Proportionality between the ratio of excimer to monomer emission intensities and the function la·faa was predicted. Good agreement with this relationship was obtained in each of the copolymer systems studied. Reactivity ratios of methyl methacrylate (rm) in copolymerization at 70°C with the aromatic monomers (ra) were determined as: 1-vinylnaphthalene—rm = 0.43, ra = 1.71: 2-vinylnaphthalene—rm = 0.37, ra = 4.46; styrene-rm = 0.45, ra = 0.58.
57 citations
TL;DR: In this article, the development of excimers and excimer lasers are reviewed and the methods of pumping, operational characteristics and applications of the lasers are discussed in terms of their structure, spectroscopy and formation kinetics.
Abstract: The development of excimers and excimer lasers are reviewed The excimers of the noble gases (Xe
2
*
, Kr
2
*
, Ar
2
*
) and of the noble gas halides (eg KrF, XeCl) which, respectively, radiate in the vacuum ultra-violet and ultra-violet regions of the spectrum are described in terms of their structure, spectroscopy and formation kinetics and the methods of pumping, operational characteristics and applications of the lasers are discussed
57 citations
TL;DR: A detailed spectroscopic investigation supported by density functional theory (DFT) calculations on two series of CBP derivatives finds that the resulting poor coupling between the two halves of the molecules leads to an electronic structure similar to that of N-phenyl-3,6-dimethylcarbazole, with a high triplet-state energy.
Abstract: Carbazole-based materials such as 4,4'-bis(N-carbazolyl)-2,2'-biphenyl (CBP) and its derivatives are frequently used as matrix materials for phosphorescent emitters in organic light emitting diodes (OLED)s. An essential requirement for such matrix materials is a high energy of their first triplet excited state. Here we present a detailed spectroscopic investigation supported by density functional theory (DFT) calculations on two series of CBP derivatives, where CH(3) and CF(3) substituents on the 2- and 2'-position of the biphenyl introduce strong torsion into the molecular structure. We find that the resulting poor coupling between the two halves of the molecules leads to an electronic structure similar to that of N-phenyl-3,6-dimethylcarbazole, with a high triplet-state energy of 2.95 eV. However, we also observe a triplet excimer emission centered at about 2.5-2.6 eV in all compounds. We associate this triplet excimer with a sandwich geometry of neighboring carbazole moieties. For compounds with the more polar CF(3) substituents, the lifetime of the intermolecular triplet excited state extends into the millisecond range for neat films at room temperature. We attribute this to an increased charge-transfer character of the intermolecular excited state for the more polar substituents.
57 citations